The invention relates to a throttle valve having a supporting plate for a device for registering the position of a moving part, especially a potentiometer.
Such a supporting plate is described in DE 34 28 006 C2. This discloses an electric module which carries a printed circuit, this module having a supporting part shaped like a table mountain, which is provided on its surface with elevations. These elevations, which may also be of elongate design, are used, in interplay with an adjusting pin on the supporting part, for the precise alignment of the printed circuit, the printed circuit having a hole to accommodate the adjusting pin and being fixed in its desired position by means of an adhesive compound and resting in a precisely defined way on the elevations. The table-mountain-shaped supporting part has an extremely complex configuration and therefore necessitates complicated production.
Furthermore, it is necessary to provide the printed circuits for the installation of the module, no statements relating to this provision being made in DE 34 28 006 C2.
The invention is therefore based on the object of configuring a supporting plate in a throttle valve as simply as possible, specifically in such a way that not only is simple installation provided but, moreover, stock-keeping is also improved. The supporting plate forms a part of a potentiometer of the throttle valve, and has an upper side on which are located resistance tracks, wiper tracks, and conductor tracks of the potentiometer. The supporting plate has an underside on which are located spacers for positioning the supporting plate on a housing of the throttle valve.
The arrangement according to the invention of spacers on one side of the supporting plate has, on the one hand, the advantage that the bearing surface for the supporting plate can be kept continuously flat to the greatest possible extent, which is advantageous, in particular, in a complex shaped supporting part. The spacers thus define a precise distance between the underside of the supporting plate and the surface of the supporting part, so that simple and precise installation is possible without further adjustment tools or apparatus being necessary. Furthermore, the invention provides the advantage that, by means of the spacers, the supporting plates can be stacked one above another in order to provide them for further processing. This is advantageous precisely in the case of mass production of registration devices or the like, since, for example on a production line, a large number of such supporting plates have to be provided one after another for continuing installation. On the one hand, it is possible for these supporting plates, following their production, to be stacked readily one above another by means of the spacers which are already present, while the removal of these supporting plates from a stack is also readily possible. In particular, automated stacking on one another or removal from the stack is possible. This avoids the supporting plates having to be handled manually, in order thus to avoid contamination (for example by traces of grease). The handling of the supporting plates can be carried out, for example, by a gripper by means of vacuum. Such spacers are particularly advantageous if sensitive coatings are applied to the other side, that is to say facing away from the side on which the spacers are arranged. Likewise, the invention dispenses with individual spacers, which would have to be placed between the individual supporting plates which are stacked on one another, during transport and during stock-keeping. By this means, in particular in large-scale mass production, the costs for stock-keeping are reduced quite significantly.
In a development of the invention, the spacers can be fastened to the supporting plate as individual studs. As already outlined, coatings, such as conductor tracks, wiper tracks or the like, or else electronic components can be arranged on one side of the supporting plate. After the supporting plate per se has been produced, individual studs are fastened to the other side, this fastening being, for example, injection-molding the individual studs on, bonding them on or the like. This has the advantage that, because of the fastening of the individual studs, all the studs or some of them can consist of a material different from that of the supporting plate. The material is advantageously chosen depending on the material of the supporting plate, so that on the one hand good fastening of the individual studs to the supporting plate is ensured. On the other hand, the material may be chosen from the point of view that the material of the individual studs is matched to the material of the surface on which the studs subsequently rest with the supporting plate. One example which may be mentioned here is that the studs consist of an elastically deformable material and can perform a damping function.
In a development of the invention, the spacers can be produced as individual studs together with the supporting plate. During the production of supporting plate and studs, this advantageously leads to a single production operation, so that the studs are already present at the same time as the production of the supporting plate.
Particularly advantageous is the production of the supporting plate in an injection-molding process, the supporting plate with the individual studs consisting of plastic. A supporting plate made of plastic has the advantage that this constitutes an electrical insulator if conductor tracks, wiper tracks and the like are arranged on the surface of the supporting plate and one or more voltages are applied. If a number of supporting plates are then stacked one above another and one surface of the supporting plate has already been coated with these wiper or conductor tracks, the result is that the damage to the surface of the wiper or conductor tracks by the supporting plate located above is effectively avoided, since the latter in turn rests with its own studs on those regions of the supporting plate located below in which there are no wiper or conductor tracks.
In a development of the invention, the spacers are designed as bearing surfaces. Alternatively or in addition to the spacers designed as studs, bearing surfaces are provided which are of greater area than the studs and thus distribute the bearing forces over a greater area. This is particularly advantageous when fastening means (for example screws or the like) are provided in the vicinity of such a bearing surface, by which means the supporting plate is fixed to the surface resting on it. Thus, in a development of the invention, the bearing surfaces are arranged in the area of fastening holes, good contact and reliable fixing of the supporting plate in its position being achieved on account of the greatest possible concentric arrangement around the fastening hole. In this case, adhesive bonding of the supporting plate to the bearing surface can be dispensed with. As an alternative to this, the studs and/or the bearing surfaces can be used for the purpose of adhesively bonding the supporting plate to its substrate via these bearing surfaces. By comparison with adhesively bonding the supporting plate to the substrate over the entire area, this saves adhesive to a considerable extent.
In a development of the invention, a number of supporting plates can be provided stacked one above another in a magazine for further processing. It is thus possible for supporting plates, after the individual studs have been fastened to them, or after the one-piece supporting plate with integrally molded studs or bearing surfaces has been produced, to be put into the magazine and stacked one above another. This has the advantage that stock-keeping and transport costs are reduced, since more supporting plates can be accommodated in the same space by comparison with the conventional deep-drawn pallets, in which the supporting plates are arranged alongside one another. Of course, it is also conceivable to line up a number of magazines in a row or one magazine with a number of compartments for supporting plates to be stacked one above another. Stacking the supporting plates one above another in the magazine has, moreover, the advantage that, for the purpose of the further processing or for the final installation of a supporting plate, the latter can be picked up automatically by an appropriately designed pick-up apparatus. It is thus possible for the further processing operation on a supporting plate (for example coating with conductor and/or wiper tracks) or, respectively, the final installation to be automated. Manual handling of the supporting plates is thus avoided, so that the supporting plates can no longer be contaminated and complicated cleaning operations before coating can be dispensed with. Furthermore, an empty magazine of an installation apparatus can simply be removed and a full magazine can be inserted in turn, it also being possible for this removal operation and the subsequent operation of inserting a filled magazine to be automated.
In a development of the invention, the magazine has webs or the like for fixing the supporting plates stacked one above another in position. Thus, on the one hand, any movement of the supporting plate within the magazine is avoided; on the other hand, this positional fixing during the removal of a supporting plate from the magazine makes any adjustment of position for the subsequent further processing operation unnecessary. Alternatively or in addition to the webs for positional fixing, outer contour points on the supporting plate, which come to rest on internal areas of the magazine, can be used for the positional fixing.
In a development of the invention, a mandrel or the like is provided, which accommodates and moves the supporting plates stacked one above another in the stacking direction, so that said supporting plates can be removed from the magazine one after another for further processing. If the supporting plate has a hole, a recess or the like or a number of these, these can be used in that the supporting plates are guided over the mandrel via this hole or the like and, for example, come to rest on the bottom of the magazine. By moving up the movable bottom of the magazine or only of the mandrel, which carries with it the supporting plate deposited first in the magazine, one supporting plate after the other can be provided for further processing by being moved up continuously or intermittently.
In a development of the invention, it is advantageously used in a potentiometer, either for registering the position of the throttle valve or for registering the position of the gas pedal for controlling the output of an internal combustion engine. The configuration of such a potentiometer is shown later in the figures, the invention not being restricted to such a potentiometer but also being used, for example, in other registration methods, for example inductive, magnetic, capacitive registration or the like.